MEMS (Micro Electro Mechanical Systems) is a micro-integrated system manufactured by integrating a microstructure, a micro-sensor, a micro-actuator, a control processing circuit and even an interface, communication unit, and a power supply on a piece or multi-pieces of chip using integrated circuit manufacturing technology and micro-processing technology. With the development of the MEMS technology, acceleration sensors and gyroscopes manufactured by MEMS technology have been widely applied to the field of automobile and consumer electronics.
A gyroscope sensor with PZT (piezoelectric ceramic transducer) construction can be simulated by a resonant circuit of RLC, which has a certain resonant frequency. In order to increase bandwidth upon application, it is required to divide a sine driving signal of the sensor into three phases of compulsory resonance, resonance maintaining, and resonance ceasing, so that the gyroscope is able to resonate rapidly in response to external triggering events. With regard to an ideal resonant circuit, the driving time point and amplitude size of the above three phases may be known by calculating a formula. However, in practice, due to craft deviation during the manufacturing process of the sensor, asymmetry or temperature-dependent property, simply applications of the formula tends to deviate from the fact.
Referring to FIG. 1, a conventional construction of a sensor driving detection is shown as 100, which includes a charge amplifier 101, a amplitude phase and angular velocity detector 102, a ADC (analog-to-digital converter) 103, a control module 104, a DDS+DAC (digital-to-analog converter) 105, a formula or look-up table module 106, and a tunable gain amplifier 107.
In order to increase a bandwidth of a sensor application, the formula or look-up table module 106 requires to output three different amplitude values to the tunable gain amplifier 107, so that the sine signal of formula or look-up table module 106 is divided into three phases of compulsory resonance 301, resonance maintaining 302, and resonance ceasing 303 to driving sensor, upon magnified by the tunable gain amplifier 107, see FIG. 3.
A time domain response of a sensor loop amplitude value may be simulated by exponential formula
      Y    ⁡          (      t      )        =            X      ⁡              (        t        )              ·    G    ·          (              1        -                  exp          ⁡                      (                          -                                                π                  ·                  f                  ·                  t                                Q                                      )                              )      upon integrated by charge amplifier 101.
Y (t) and X (t) respectively denote a time domain signal output by charge amplifier and sensor drive, G is a loop gain from sensor to charge amplifier, Q value is a quality factor of the sensor, f is a resonant frequency of the sensor.
If we want to make the output of the charge amplifier carry out angle velocity detection upon A2·G amplitude, driving signal intensity proportion of three stages of tunable gain amplifier 107 may be calculated according to resonance oscillation loop formula as follows:                compulsory resonance:        
                              A          ⁢                                          ⁢          1                =                                            1                              1                -                                  exp                  ⁡                                      (                                          -                                                                                                    π                            ·                            f                            ·                            T                                                    ⁢                                                                                                          ⁢                          1                                                Q                                                              )                                                                        ·            A                    ⁢                                          ⁢          2                                    (        1        )            resonance maintaining: A2=A2  (2)
                              A          ⁢                                          ⁢          3                =                                                            exp                ⁡                                  (                                      -                                                                                            π                          ·                          f                          ·                          T                                                ⁢                                                                                                  ⁢                        3                                            Q                                                        )                                                            1                -                                  exp                  ⁡                                      (                                          -                                                                                                    π                            ·                            f                            ·                            T                                                    ⁢                                                                                                          ⁢                          3                                                Q                                                              )                                                                        ·            A                    ⁢                                          ⁢          2                                    (        3        )                            resonance ceasing:        
where T1 is time of compulsory resonance, T3 is time of resonance ceasing, T1 is generally equal to T3.
Formulas (1) (2) (3) are derived based on ideal RLC loop response signal model, but due to deviation from manufacturing gyroscope itself, it tends to make its actual response deviate from ideal model, thus the driving amplitude calculated simply using formula or look-up table can often be not able to reach the amplitude required to maintain steady resonance oscillation, whereas the precision that influence angular velocity sense, especially when the gyroscope cause a response attenuation due to usage or temperature influence, driving according to the conventional method also reduce the sensibility of corresponding sense velocity.